Mr Smith, who quit last month after admitting his contacts with News Corp lobbyist Fred Michel had got too close, insisted he had not been given any specific instructions by Mr Hunt or civil servants on his role in the quasi-judicial decision on BSkyB.

He said he had assumed he should be "managing relationships" with interested parties – but conceded that his only communications were with News Corp.

Mr Hunt's briefing note to the Prime Minister was prepared barely a month before the Culture Secretary was put in charge of the BSkyB decision, after Mr Cable was caught out voicing his opposition to the bid.